Get Table name and Primarykey using java Program

package com.sampleproject;

import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;


public class GetallTableNames {

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub

System.out.println("now we are going to connect with a database ");

 try {

  Class.forName("com.mysql.jdbc.Driver");

  Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "root");
  DatabaseMetaData md = con.getMetaData();
  ResultSet rs = md.getTables(null, null, "%", null);
  String   catalog   = null;
  String   schema    = null;
  String   tableName = null ;


/*while(result.next()){
   String columnName = result.getString(4);
}*/
while (rs.next()) {
 System.out.println(rs.getString(3));
 tableName = rs.getString(3);
 String columnName = null;
 ResultSet result = md.getPrimaryKeys(
   catalog, schema, tableName);
 while(result.next()){
 columnName  = result.getString(4);
 System.out.println("primary key :" +columnName);

}

}
}
 catch (Exception e) {

  System.out.println(e.getMessage());
 }
}
}